The Discovery was introduced into the United Kingdom in 1989. The new model was based on the chassis and drivetrain of the more upmarket Range Rover, but with a lower price aimed at a larger market segment and intended to compete with Japanese offerings. This was the only Discovery generation with four-cylinder engines.

The Discovery was initially available in a three door version. The five door became available the following year. Both were fitted with five seats, and an option was made available to have two further seats fitted in the "boot" area at the back of the car.

Pre-1994, the Discovery was available with either the 2.5 litre 200 Tdi engine or the 3.5 litre Rover V8. Early V8 engines used a twin SU carburettor system, moving over to Lucas 14CUX fuel injection in 1990.A 2.0 litre petrol engine from the Rover stable was briefly available in a model known as the 2.0 L Mpi I4. This was intended to attract fleet managers, since UK (and also Italian) tax laws benefited vehicles under two litres. A combination of changes in taxation and the engine being underpowered for such a heavy vehicle led to the demise of this engine, despite the kudos of being the engine fitted to several Discoveries supplied to the British Royal family, most notably driven by Prince Philip around Windsor Great Park, in his position as Park Ranger of the park. In 1992 the Discovery received several additions and improvements. The interior was now offered in a more traditional beige as well as the distinctive (but controversial) light blue, an automatic transmission was made available on 200Tdi models, new colours were added to the range (and the large 'compass and mountain' side decals worn by early Discoveries were removed) and the 'SE' pack incorporating alloy wheels, front driving lights, roof bars and a special range of metallic paints was introduced as an option.

In 1994, many changes were made to the Discovery and reached some markets as "Discovery 2"; the 200Tdi and 3.5 L V8 engines were replaced with the 2.5 L 300TDi 4-cylinder and 3.9 L Rover V8 engines, the 300Tdi introducing a Bosch electronic emissions control for certain models and markets. At around this time a stronger R380 gearbox was fitted to all manual models combined with the flexible cardan coupling GAJ-1 from SGF for more comfort. The newer models featured larger headlamps and a second set of rear lights in the bumper. The new rear lights had the wiring changed several times to meet real or expected European safety legislation. Some vehicles are left with an arrangement where the vulnerable bumper contains the only working direction-indicator lights; other examples have these lights duplicated in the traditional rear pillar location.

The designers of the original model had been forced to economise and use the "parts-bin" of the then parent-company, Rover. The 200 series used the basic bodyshell structure from the Range Rover, door handles from the Morris Marina, tail lights from the Austin Maestro van, and interior switchgear and instrumentation from the Rover "parts bin". The favour was returned when the facelifted Discovery dashboard was also fitted as part of the final facelift to the first-generation Range Rover, though with minor differences reflecting the vehicle's higher status, such as an analogue rather than digital clock.

Technically speaking, the 1996 to 1998 US models with 4.0 L engines had the same displacement as the 3.9 L engines fitted to the earlier 1994 to 1995 US models; the differences between the engines involved improvements to the block rigidity and pistons, and a change from the Lucas 14CUX engine management to the distributorless Generic Engine Management System ("GEMS"). In earlier 3.9 L US engines the fuel injection computer (14CUX) did not control the ignition, which was instead controlled by a traditional system with ignition coil and distributor made by Lucas. The 4.0 L engines had a few important differences: larger, cross-bolted main bearings, revised pistons, revised intake and the GEMS system. It was developed jointly by Lucas and SAGEM and it controlled both spark and fuel injection. Unlike the earlier systems fitted to Rover V8 engines, GEMS was made OBD-II compliant. This change was largely driven by the federal requirement (starting in 1996) for vehicles sold in the United States to meet the OBD-II specification.

As with all Land Rover vehicles designed since the Series models, which had switchable two-wheel and four-wheel drive, the transmission is a permanent four wheel drive system, with a locking centre differential at the transfer box. In common with much of the rest of the Land Rover range, the handbrake acts on the transmission at the back of the transfer box, therefore locking all wheels when applied.

In Japan, a badge-engineered version of the Series I was offered, called the Honda Crossroad. The Rover companies had cross-holding relationship with Honda U.K. since early-1980s. The relationship ended after Rover was taken over by BMW in 1994. (Honda revived the nameplate 'Crossroad' in another small sport utility vehicle in 2007.)